Time delay relay



Jan. 16, 1951 Filed May 31, 1946 W. D. MACG EORGE NVENTOR #444/4/1/ QMCGfO/QGA ATTORNE a 1951 w. D. MACGEORGE 2,533,732

TIME DELAY RELAY Filed May 51, 1946 2 Sheets-Sheet 2 INVENTOR Mu MM 5A/JGGZORGE @Z M v%%;

ATTORNEYS Patented Jan. 16, 1951 to Automatic Temperature Control 00.,Inc., Philadelphia, Pa., 'acorporation of Pennsyl vania Application May31, 1946, Serial No. 673,683

8 Claims.

This invention relates to time delay relays. It is among the objects ofthe invention: to provide improvements in time delay relays; to providea double time delay relay by which the time of make of relay as well asthe time of break of the relay, after respective making and interruptionor breaking of the circuit thereto, are independently timed; to providea double time delay relay for operating a Thyratron control circuit orthe like by which, after closing the circuit, a predetermined timeinterval elapses during which the Thyratron tube is heated before theload circuit is established, and which, pursuant to a temporaryinterruption of the current for an interval less than that for which thedevice is predetermined, closes the load circuit again, withoutrequiring such predetermined time interval to elapse and which, in'theevent that the Thyratron has had time to cool below the safety point,reestablishes the preliminary warm-up time interval, the elapse of whichis a prerequisite to the sequential closing of the load circuit; toimprove differential mechanisms: to improve differential mechanisms forpartial strokes; to improve the indicating qualities of time relays andthe like; and many other objects and advantages of the invention'willbecome more apparent as the description proceeds.

In the accompanying drawings,

Fig. 1 represents a front elevation of the differential time delay relayof this invention, at the start of a timing interval prior to relaycircuit closing. 4

Fig. 2 represents a transverse'section taken on line 2-2 of Fig. 1.

Fig. 3 represents a lateral section taken on line 3--3 of Fig. 2.

Fig. 4 represents a plan, partially in section, of the device of Fig. 1.

Fig. 5 represents a view similar to Fig. 1 with anchors the pinion gearII against rotation. On

parts broken away and with the relay at the close of the timing intervalat the closing of the So far as the preferred form of the relay isconcerned, it preferably comprises a unidirectional motor I0, supportedon one side of a panel board 24, and driving a pinion gear II on the anaxis parallel to that of the pinion gear II, a shaft I2 is journalled onthe panel board 24, and toward the front end the shaft pivotally carriesthe depending lever arm I3, hanging or depending substantiallyvertically and movable in a con-- trollabl'e, relatively slight,oscillation 32 between its normal position held against the adjustablestop I4 by the spring deviceI5, andthe operating stud I6 of amicro-switch or the like II. A large sprocket I8 is journalled on ashaft 20 carried by the operating lever I3, in mesh with the alternateor selective driving stop pinion II. It will be seen that in a movementof lever I3 counterclockwise of and about the shaft I2 from its positionof normal rest against the stop I l, the transverse movement of thelever I3 will impart rotation to the sprocket I8, when the pinion II isheld locked. As viewed in Fig. 1, this rotation of the sprocket I8 willbe clockwise. In a reverse movement of the lever re-traversing path 32,in moving from stud I6 tostop I4, the sprocket I8 is shifted bodilyacross the peripheral edge of the adjacent portion of the pinion I I ina counterclockwise direction of rotation. Although an exaggeratedmovement of the lever in either direction would bring the teeth ofsprocket I8 out of mesh with the pinion gear II, this is guarded againstin the normal operation of the device in nalled on the shaft I2,concentric witli the axis.

of the pivot of the lever I3, and the gear 2I is also in constantdriving relation to the relatively small pinion gear 22 mounted on ashaft I9 journalled in the panel 24 and carrying a larger gear 23 on therear face of the panel. The gear 23 on the back of panel 24 is in meshwith a relatively small pinion gear 25, of a shaft carrying therelatively large brake drum or stop gear 26. It will be observed thatwith drum 26 free to turn, the rota.- tion of the motor driven pinionII, through its meshing engagement with the sprocket I 8, will drive theentire train of gears, including the terminal drum element 26, in idlerotation while the lever arm I3 remains against the stop I4, unaffectedby the drive from motor Ill. On the other hand, if the drum 26, and thusthe entire train of recited gears to and including sprocket I8, islocked and held against rotation, then the driven rotation of pinion II,in its meshed engagement with the locked sprocket I8, causes sprocketI8- to function as a transversely movable rack, and by forcing thesprocket I3 to climb transversely on pinion II, it moves or takes thelever I3 with it transversely across in front of panel 24. This causesthe lever I3 to leave stop I4 at the beginning of the timed intervaldetermined by the closing of the circuit through the motor, and totraverse the, predetermined distance 32 between the edge remote from thestop I4 when in engaged relation thereto, and the control knob orbutton, It of the single pole, double thrown switch, such as a microswitch IT. This desired timed interval could only happen, however, whenand; if the terminal gear or brake drum 26', and thus the; entire geartrain, was locked against rotations.

To look the gear 26, selectively, an electromagnet Z'l is mounted on thepanel 24, and is.

the periphery of the gear 26, to form a positive stop to the rotationsof the gear train when the magnet is energized. When the magnet isdeenergized, in the normal course, the lever arm 28 snaps up under thebias 29, removing. the tooth detent 30 from the meshed engagement withthe ear 26.

The detent 30 on the lever 28 is located slightly off center, as far as.a vertical plane containing the axis of the brake drum or gear 26 isconcerned, and this fact, in addition to the almost inevitable presenceof a small residual back lash in the relatively long gear train, and theresilience of the lever 28, enables the detent 30, to enter directlybetween the. teeth of the gear 26, regardless of the setting of theadjustable stop I4, and it also enables easy and quick removal of thedetent 36 from gear 26 when the electro-magnetic circuit is broken andthe spring- 29 functions to snap the lever upwardly and away from thegear 25.

By coupling the motor I and the electro-magnet 21 in parallel with thepower source, as shown in Fig. 6, with the circuit through the motoronly passing through one side iii of the single pole, double throw, snapswitch ll, there will be simultaneous energization of both the motor andthe magnet when the main power switch 39 is closed. The electromagnet 21is energized simultaneously with the starting of motor l0 and the detent30 snaps in, to lock the gear train, and the rotatably locked sprocket.I8 starts to move transversely across the face of the panel 24, about:pinion II, driven by the motor It. If the closing of this circuit hasalso been accompanied by the closing of the circuit through the cathodecircuit of the Thyratron tube, if this is the timed associated element,then by the time that the. lever I3 has moved across; the gap 32(Fig. 1) to. a point such as to actuate the knob or control element I6oi the switch H, the cathode circuit of the Thyratron has been on for asafe period so that the load circuit 343' controlled by circuitcontroller 33 of the switch I'l, can be cut in through the anode circuitof the Thyratronf This is accomplished by opening the circuit throughthe motor Iii, through circuit controller 3I of switch II, which stopsthe motor and holds the pinion I I stationary and thus the lever I3 inits extreme timed positioning against the actuating control device It.If everything proceeds properly, this is the operating condition, withdetent 30 still engaged to lock the gear train and the motor I0 stopped,and with the load circuit coupled to the power lines.

With the parts as so far described, it will be understood that it willbe necessary to start and q complete a new timed delay cycle before thepower lines can be coupled to the load circuit after a break in thepower circuit. This is assuming or the sake of the description that thepower lines, are common to both the relay and to the load circuit. Itwill be clear that in the event of even a most transient stoppage of thepower line supply, as when changing generators, for instance, theinterruption of the circuit through the electr c-magnet 2'! enables thespring 29 to function to snap the lever 28 upwardly on its pivot towithdraw the detent 30 from the gear engagement. This instantly removes,the brake from the gear 25 and under the action of the spring I5efiective on the lever IS, with the freely rotatable sprocket rotatingabout the stationary pinion Ii, the lever 23- snaps over intoengagement. with the abutment I4, which simultaneously removes thepressure from actuator I6 of, the snap switch I], to successively breakthe load circuit. through the circuit controller 33, and to reestablishthe connections with the power line circuit for ultimate closing of thecircuit. through the motor II] when the power circuit isreestablished... This condition, maintains with, no further action untilthe power line circuit againbecomes closed, when the electro-magnet 27again snaps the detent. 30 into mesh with the gear 25 as the motor Itstarts to run, to establish another timed interval before the loadcircuit again is; closed through actuation of the switch II. The relaywith its timed delay as described, is of value in many situations where,safety is more important, than the mere saving of time, It will. beseen, however, that: if the break. in the power supply is purely transi-I! tory, even for a few seconds, perhaps the Thyratron would not have achance, to cool to a point below which it would. be safe; to reenergize:same immediately after the power lines. were reestablished, following ona break therein; In other words, from the, safety standpoint, even.opening of the cathode circuit for as long as twentyseconds, as a,purely illustrative. instance, and then closing it would find the outputof the tube from the anode. circuit, when. also reenergized, adequatefor the load purposes. placed? upon it. Thus, if the cathode circuitwere closed again within the safe limits and the load circuit were alsoclosed again within the same safe limits, it will be clear that it wouldbe a waste of time to be forced to. await the complete timed cycle ofoperation incident to bringing the lever 13 from its repose against theabutment l4. through the timing cycle to a point of actuating the switchH.

In order to. effect a safe timed delay on the break, as well as on themake, of the work or load circuit, it is preferred to provide a thermallatch 34', comprising a suitable bi-metallic device energized by thesecondary of" a transformoi: 3.5,, theprimary of: which is connecteddirectly across the power circuit. The lei-metallic element 34 has alatching flange 31 juxtaposed to the free endoi the lever: 28 and is soarranged that when suitably heated by the flow of current through theelement, for a sufficient time interval, the latch flange 3?; moves overthe. nee

end of the depressed lever 28, which at the time, of course, has beenpulled in by the electromagnet, as shown in Fig. 5. mother words,

- had been no interruption; This saves repeating when the master circuitswitch 39 is closed through both power lines, the electro-magnet 21 isenergized, pulling in the lever '28, and at the same time thebi-metallic element 34 is energized and begins to warm up. With a timedelay, which is preferably adjustabl to accord with. the various uses ofthe device, by relative adjustments of the support 36 to move the latch31' in its plane toward or away from the end of lever 28, the flange 31of the latch moves slowly across the lever, 28 in increasing overlappingcontact therewith as the element 34 becomes hotter. As long as thebi-metallic element retains sufficient heat to maintain a suitable bend,the flange 31 thereof latches the lever 28 by overlapping same and holdsit against rising to release the detent 3&3 from the gear 26. With thesecondary timed delay arrangement just described, it

may well be that for the purpose of savingpower, I

the electro-magnet 21 and the motor H] are arranged in parallel and bothare controlled by the circuit controller 3| of switch [1,, so that whenthe predetermined timed interval between the starting of the motor Itand the breaking of the circuit through switch elements 3| of switch Hhas elapsed, and the load circuit has been established through theswitch elements 33, both the motor 10 and electro-magnet 21 aresimultaneously deenergized, and remain so during the continuance ofuninterrupted flow through the power lines. As during this entire time,however, the circuit has been flowing in the bi-metallic element 34,flange 31 thereof has attained a maximum overlap on the lever 23, forwhich it is designed, and holds the lever 28 "in with the detent 3Bengaging and locking gear 26 so that the gear train meshing therewithremains locked. Itis preferred, however,

that-the circuit connections for the electro-mag' net be similar tothose disclosed in Fig. 6.

When there is an interruption in the power lines, which if held too longwould endanger the Working or load circuit elements, if the loadcircuits were remade immediately when the break ended with the remakingof the power circuits, the first activity following upon the break ofthe; line connection, is the opening of the circuit through theelectro-magnet 27, and the imposition of the spring bias to urge thelever 28 out.

This is ineffective, however, because of the latching function of flange31. At the same time, the heating circuit through the bi-metallicelement 34 is interrupted and the element starts to cool. As it cools,it straightens out and gradually withdraws the flange 31 fromoverlapping the lever 23. If at any time before complete withdrawal ofthe flange 31 from its overlyinglatching relation with the lever 28, thepower circuit is again completed, that is, within the time set bytheinitial normal disposition of the bi-metallic element 34 and flange 31relative to the lever 28, the power lines through the load arereestablished instantaneously. This is because the lever [is hasremained in operative contact with the actuating stud it of the switch11, the latter remains with circuit controller 33 thereof closed, and,therefore, the motor Ill and electromagnetic coils 2? controlled bycircuit controller 3| of that switch, have not been placed in circuitwith the power lines. As the load circuit the time delay before the loadcircuit can be reestablished and speeds up the operation of the machineassociated with the relay.

When, however, the duration of the break in the power line exceeds thatfor which the device is preset, the bi-metallic element 34 has an opportunity to cool sufficient as to completely withdraw the flange 3'!from the overlapping relation tothe lever 28, which promptly snapsupwardly, withdrawing the detent 30 from the gear, which is immediatelyfollowed by the rapid idle rotation of all of the gears in the trainunder the urge of the spring bias l5, permitting the lever is to moveaway from the switch H to engage the abutment M, and thus to set theconditions for the ultimate reestablishment of the actuating circuit, bywhich to restart the load circuit after the predetermined delay prior tosuch restarting incident to the movement of lever I3.

It will be' evident that in many cases it is of importance to know howfar along in a given cycle of operations the timing delay device may be,and to this end suitable indicating means is associated with parts ofthe mechanisms having preferably an oscillation of less than 360 in thenormal operation of the device. To a suitable member of restrictedangular movement, such as to. the shaft IQ. of the first pinion gear 22in the train above the sprocket [8, a pointer 41! is affixed inposition'to overlie the graduations of the indicating dial 38, and soarranged as to move on its axis in shaft is as a relatively smallangular ,function of the angular movement of the lever I3 in its timingfunction movement. Of course, for this purpose also, the indicator 4!!could be carried directly by the lever 13 for the same effect.

It will be apparent that if with the gear train completely locked sothat the sprocket l8 climbs transversely over and relative to therotatin pinion gear 8 l actuated by the motor, the lever it moves agiven fraction of an inch in a given time interval, then if the brakingon gear 26 were look the gear train from above similarly to the lockaccomplished by the detent 36 on gear 25. On, the other hand, if gear 25were driven in a given direction at a given different rate of speed fromthat at which the pinion gear I l were driven, the progress of the lever13 would be as the diiferential between the two speeds, or as the sum ofthe two speeds if the directions of rotation were properly coordinatedfor the purpose. It will be seen that with the device as shown in Fig.8, with motors 3| and I0 turning in mutually cancelling directions atnearly the same speed, the rate of rate indeed. The possibilities witheither different speeds of the motors, or with diiferent ads justmentsfor speeds of the respective gears ii and 25, for adjustable timingintervals for timing relay purposes are practically without limit.

'The advantages of the invention will be apparent to those skilled inthe art.

Having thus described my invention, I claim: 1. A time delay relaycomprising a lever having an arc of movement about a pivot, a sprocketassays a gear, means for mounting the sprocket gear "ro tatably on andfor bodily movement with the lever between the pivot and the freeend ofthe lever for movement in translation with said lever, a pinion gearmeshing with said sprocket gear on the opposite side of said sprocketfrom said pivot and fixed against translational movement, motor meansfor driving the pinion in one direction,

stop means, spring means urging the lever toward one side of its arc ofmovement against said stop means, a switch, operating means for theswitch located at the other side of the said are of movemom of saidlever, electrical means selectively operable for locking said sprocketagainst rotation and for unlocking said sprocket, means for operatingsaid electrical means, means independent of said electricalmeansestablishing anoperating circuit for the motor means through said switchbroken when said switch operating means is actuated by said lever, saidsprocket when locked serving as a toothed rack member movable bodily bythe pinion to move the lever in a timed interval through its arc ofmovement to engage and actuate said switch-operating means to stop themotor and hold said lever against said switchoperating means. until saidmeans for operating is actuated to unlock said sprocket to permit thelever to leave the engagement with the switchoperating means under theinfluence of said spring.

2. A time delay relay comprising a frame, an element supported on theframe for movement from a starting position to a final switch-actuatingposition, a sprocket journalled on said means and movable bodilytherewith, a motor, a pinion gear journalled on the frame and in meshwith the sprocket gear, means operatively coupling the motor and thepinion gear to drive the latter when the motor runs and to hold thepinion gear stationary when the motor is stationary, a switch having twopositions and controlling two different circuits, means located at saidswitch actuating position and engageable by the movable means to openand close the two different circuits in alternation, means locating saidmotor in one of said controlled circuits for running the motor until theswitch has been actuated by said movable means, means operative duringthe time of running of said motor at least for locking said sprocketagainst rotation during rotation of the driven pinion to secure themovement of said means, a load circuit controlled by the other'of thetwo controlled circuits of the switch which is closed when the movablemeans engages the switch actuating means to open the circuit through themotor, and thermal means holding said locking means in looking operativerelation to said sprocket to prevent rotation of the sprocket relativeto the stationary pinion for a predetermined interval, and means urgingthe movable means from its switch actuating position to the variablestarting position operative when the sprocket is unlocked for rotationon the 'statiom ary pinion gear.

3. A time delay relay comprising a gear train having primary andsecondary terminal gears, a member movable in a predetermined pathbetween limits, spring means urging the member against one of saidlimits, one of said terminal gears mountedrotatably on'said'member, apinion gear fixed for rotation adjacent to said path and in mesh withthe terminal gear mounted onsaid member, a motor for driving the piniongear, electro-magn'etic means for brakingthe otherof saidterminal gearsto lockthe gear train'against rotation, means for'energizing the electrc-magnetic means and the motor to cause the pinion gear todrive thelocked terminal member to move the member away from one limit toward theother in a timed interval against the resistance of said spring means, atwo position'switch having contacts such that in a first unengagedposition of the switch a circuit through said motor is established, andin the other position the circuit through the motor is broken and acircuit is established through a load, means at the limit'of thepredetermined path operable by said member the circuit through the motorwhile breaking the load circuit, and thermal means for delaying for apredetermine'd'interval the release of the braking means after theinterruption of the circuit through the electro-magneticmeans.

4. A time delay relay comprising a frame, an element supported on theframe for movement between starting and switch actuating positions, asprocket journalled on said element and movable bodily therewith, amotor, a pinion gear journall'ed ontheframeinmesh with the sprocket andin drivenengagement w-ithsaid'motonmeans for urging the element "towardits starting position, means'foi" locking the sprocket againstrotationto enable driven actuation of the pinion to move the element from itsstarting position toward its switch actuating position against theresistance 'of the mean's foru'rging at a timed rate, and separatemeanshaving a predetermined time delay for releasing the means forlooking to permit the sprocket to turn idly relative to the pinion whilemoving bodil with-said'element to enable the means for urging theelement tomove it to its starting position.

5. A time delay relay comprising a frame, an element supported on theframe for movement from a starting to a switch actuating position, asprocket journal-led on said element and movable bodily therewith, amotor, a pinion gear journalled ontheirain'ein mesh with the sprocketand in driven engagement with said motor, means for urging the elementtoward its starting position, means for locking the sprocket againstrotation to enable driven actuation of the pinion to move the elementfrom its starting position toward its switchactuating position againstthe resistance-of the means for urging at'a timed rate, said lockingmeans including an electromagnetically operated device and means closinga circuit therethrough in effective parallelism with the circuit throughthe motor, a switch in position to be actuated by said element at theend of its movement and including a circuit controller through whichthe-motor circuit passes, means establishing'a loadcircuit, a circuitcontroller for the load circuit controlled by said s'witchin alternationtothe motor circuit, and a thermal latch, means establishing a circuitthrough the thermal latch in effective parallelism with the circuitthrough the electro-magnetic device, said latch when suitably heatedbeing arranged as-a d'etent to therel'ease of said brake when theelectromagnetic circuit is broken, and arranged when suitably cooledtopermit the release of said elect'ro-magnet icdevice.

6. A double time delayrela-y comprising a sup-- 9 port, an elementmounted for pivotal movement about the axis on the support, a sprocketgear journalled on the element for bodily movement therewith, a gearconcentric with said axis in permanent mesh with said sprocket, a trainof gears in mesh with said concentric gear and terminating in a brakinggear rotatable on the support, a pinion journalled on the support and inpermanent mesh with the sprocket, a motor for driving the pinion, astop, a spring for urging the element against the stop, aswitch-actuating means spaced from the stop in the path of movement ofsaid element, a lever overlying said braking gear, resilient meansurging the lever away from said braking gear, electro-magnetic unlockthe train of gears but operative when,

cooled to withdraw said flange to permit such unlocking, and meansestablishing a circuit through the thermal element effectively inparallel with the circuit through the electro-magnetic means, saidthermal element arranged to impose a time interval after theinterruption of the circuit through the electro-magnetic device and thethermal unit before permitting unlocking of the train of gears and theiridling rotation in moving the element back toward the starting position.a

7. In time delay relays, a support, a lever, means mounting the leverfor oscillation on a pivotal axis relative to the support, a sprocket,means mounting the sprocket for rotation on the lever on an axisparallel to the said pivotal axis, a first and a second abutment meanson the support in relatively spaced relation in and limiting the path ofoscillation of said lever, a circuit controller having a yieldableactuating element, one of said abutment means comprising the yieldableelement of said circuit controller, motor means, circuit means for themotor controlled by said circuit controller, a pinion gear mounted onthe support in driven relation to the motor means on an axis parallel tosaid pivotal axis generally between said first and second abutment meansand in mesh with said sprocket, electrical means independent of the saidcircuit means operable selectively to unlock or lock said sprocketagainst rotation on its axis, the spacing between the abutment meansbeing closer than would permit the pinion and sprocket to unmesh throughrelative bodily movement of the sprocket with the lever, means forbiasing the lever toward one abutment means, said sprocket when lockedby said independent electrical means functioning as a rack to move thelever against its bias under torque from said pinion during the closingof the motor circuit, said circuit controller opening said circuit tostop the motor when the yieldable member thereof has been engaged bysaid lever with the lever continued in engagement with said yieldablemember, and said sprocket when unlocked by said electrical means turningfreely to permit the lever to respond to the bias and move toward theabutment means toward which it is biased regardless of the running ofsaid motor initiated by closing of the motor circuit when the yieldablemeans is released by said lever.

8. In time delay relays, a frame, a lever, means mounting the lever in asubstantially pendular suspension'on a pivotal axis to the frame, asprocket, means mounting the sprocket on the lever on an axis inparallel spaced relation to the pivotal axis, an adjustable abutment onsaid frame in the path of arcuate swing of said lever generally on oneside of a substantialy vertical line passing through said pivotal axis,switch means comprising an abutment element in the path of arcuate swingof said lever generally on the other side of such substantially verticalline and transversely spaced from said abutment, a pinion gear, meansmounting said pinion gear on the frame on an axis parallel to thepivotal axis on the other side of said sprocket from said pivotal axisand disposed generally medially between the abutment and said abutmentelement, a motor for driving said pinion gear, said pinion gear being inconstant mesh with said sprocket and the spacing between the abutmentand said abutment element being sufliciently close as to limit thearcuate swing of said lever between the abutment and the abutmentelement always to a swing smaller than would be necessary to unmesh thepinion gear and sprocket pursuant to bodily translation of the sprocketwith said lever in its arcuate swing, means for biasing the lever towardthe abutment, separate electrical means for selectively locking andunlocking said sprocket to prevent or permit rotation of said sprocketon its said axis on the lever, said sprocket when locked functioning asa rack to move the lever against its bias under torque from said piniongear and when unlocked turning freely relative to said pinion gear topermit the lever to respond to the bias in returning to engagement withsaid abutment, and circuit means independent of said separate means forselectively locking controlled by said switch means for stopping saidmotor when the lever engages the abutment element.

WILLIAM D. MACGEORGE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number

